1. Field of the Invention
The present invention relates to an improvement of a longitudinally slidable seat structure and a reclinable seat structure installed in a two- or three-wheeled vehicle.
2. Description of Background Art
A two-wheeled motor vehicle which has a tandem seat permitting the seat position to be changed is known from Japanese Patent Laid-Open No. 2002-145143 (FIG. 4). In FIG. 4 of Japanese Patent Laid-Open No. 2002-145143, the reference numeral 26 denotes a rail member, numeral 27 denotes a slide member, numeral 29 denotes an engaging member, and numeral 29 a denotes an operating portion. The slide member 27 , which is slidably attached to the rail member 26, can be disabled from movement by the engaging member 29 and be made movable by the operating portion 29a. 
In the case of a two-wheeled motor vehicle, unlike a four-wheeled vehicle, there sometimes occurs a case where a part of the body of a rider comes into contact with the operating portion 29a unconsciously when the rider gets on or off the vehicle or when the rider moves while pushing the vehicle or passes beside the vehicle, with consequent change of the seat position. Therefore, even in the case of a slidable seat, it is desired for the seat to be capable of being kept unslidable except when the rider intends to slide the seat.
A two-wheeled motor vehicle having a reclinable seat is also known from Japanese Utility Model Publication No. Sho 57-10948 (FIG. 3). In FIG. 3 of Japanese Utility Model Publication No. Sho 57-10948, the reference numeral 2 denotes a seat portion, numeral 7 denotes a reclining device, numeral 15 denotes a back rest, and numeral 16 denotes an operating handle. The angle of the back rest 15 can be adjusted by operating the operating handle 16.
In the case of a two-wheeled motor vehicle, unlike a four-wheeled vehicle, there sometimes occurs a case where a part of the body of a rider comes into contact with the operating handle 16 unconsciously when the rider gets on or off the vehicle or when the rider moves while pushing the vehicle or passes beside the vehicle, with consequent change of the angle of the back rest 15. Therefore, even in the case of a reclinable seat, it is desired for the seat to be capable of being kept unreclinable except when the rider intends to recline the seat.